(Uljanin, 1884)

Description
— Gonozooid rather small, 3-9 mm with thin and delicate test. Intestine dextrally coiled, anus median. The testis is in an oblique line forward and upward, reaching to almost M2 (however, there is large variation in the position of the frontal end, it may reach only M5 but can extend also to M1). The developing testis extends forward in the body cavity, growing gradually to the left and pressing between M3 and the body wall, eventually outside M2 also. Ovary ventro-lateral near M7. Gills in numerous pairs, attached anteriorly and dorsally behind M3, extending rearwards, curving just before M6 and turning forwards to the attachment point at M5. Endostyle long, from between M2 and M3 to almost M5. Dorsal nerve ganglion just behind M3. Anterior aperture with a twelve lobed fringe, posterior aperture with an eight lobed fringe.
The variety Dolioletta gegebauri var. tritonis Herdman, 1888 is larger and more oceanic than the form described here above (Dolioletta gegenbauri s.s.). It can be up to 17 mm in length and the gill slits extend further forward and are attached just in front of M5.

Size
Length of test 3-9 mm, even 15 mm

Depth range

Distribution in the North Sea
Northern North Sea

World distribution
Northern, Central and subtropical S Atlantic Ocean; tropical and temperate SW Indian Ocean, tropical W and SW Pacific Ocean; also in the Mediterranean Sea.

Kingdom Animalia
Phylum Chordata
Subphylum Tunicata
Class Thaliacea
Order Doliolida
Family Doliolidae
Genus Dolioletta
Species Dolioletta gegenbauri

Status in World Register of Marine Species

Accepted name: Dolioletta gegenbauri (Uljanin, 1884)

Scientific synonyms and common names

Doliolum gegenbauri | Uljanin, 1884
Doliolum (Dolioletta) gegenbauri | Harant and Vernières, 1938
Doliolum tritonis | Herdman, 1888
Doliolum (Dolioletta) tritonis | Harant and Vernières, 1938
Doliolum ehrenbergi | Uljanin, 1884

Edwards, M., A.W.M. John, H.G. Hunt and J.A. Lindley, 1999. Exceptional influx of oceanic species into the Notrth Sea. J. mar. biol. Ass. UK, 79: 737-739.

Fraser, J.H., 1947. Thaliacea — II. Family: Doliolidae. Fiches d'Identification du Zooplancton, 10 (1947). Conseil International pour l'Exploration de la Mer, Kopenhagen.

Fraser, J.H., 1964. The Continuous Plankton Recorder Survey: plankton around the British Isles during 1964. Ann. Biol., 21: 56-62 (Cons. Perm. Int. Expl. mer).

Fraser, J.H., 1981. British pelagic tunicates. Synopses of the British Fauna (New Series), No. 20. Cambridge University Press, Cambridge. 57 pp.

Godeaux, J., Q. Bone and J.-C. Braconnot, 1998. Anatomy of Thaliacea. In: Q. Bone (ed.), 1998. The biology of pelagic tunicates. Oxford University Press, Oxford. pp 1-24.

Godeaux, J., 1998. The relationships and systematics of the Thaliacea, with keys for identification. In: Q. Bone (ed.), 1998. The biology of pelagic tunicates. Oxford University Press, Oxford. pp 273-294.

Hunt, H.G., 1968. Continuous Plankton Records: Contribution towards a plankton atlas of the North Atlantic and the North Sea, Part XI: the seasonal and annual distribution of Thaliacea. Bulletin of marine Ecology, 6: 225-249.

Lindley, J.A., J. Roskell, A.J. Warner, N.C. Halliday, H.G. Hunt, A.W.G. John and T.D. Jonas, 1990. Doliolids in the German Bight in 1989: Evidence for exceptional inflow into the North Sea. J. mar. biol. Ass. U.K., 70: 679-682.

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